Tube writing pen, particularly for automatic drawing machines

ABSTRACT

A stylographic or tube writing pen including an internal bore and an axially movable drop weight therein mounting a clearing wire, the external surface of the drop weight having a helical recess extending at least partially into an ink reservoir, and the drop weight being rotatable to facilitate feeding of ink from the reservoir to the writing point of the pen. The pen is especially useful for automatic drawing machines wherein writing or tracing speed is limited by the rate of available ink supply flow to the pen point.

[ 1 Jan. 16,1972

[56] References Cited UNITED STATES PATENTS i 1 TUBE WRITING PEN, PARTICULARLY FOR AUTOMATIC DRAWING MACHINES 3 169 821 2/1965 Miller .l ....346/l40 [75] Inventors P F Uelzen 3,594,092 7/1971 Dicario................................4o1 258 mg, Quickborn, both of Germany KOH-I-Noor Assigneei pi g ph, Primary ExaminerJoseph W. Hartary Blo m y. NJ. Att0rney--David H. Semmes Feb. 2, 1972 Appl. No.: 222,873

[22 Filed:

ABSTRACT A stylographic or tube writing pen including an inter- Forei n A cation Prior Data nal bore and an axially movable drop weight therein g pp y mounting a clearing wire, the external surface of the drop weight having a helical recess extending at least Feb. 4, I971 Germany........ ............P 2! 05 131.0

partially into an ink reservoir, and the drop weight [52] US. Cl....................346/l40, 222/4l3,40l/258 being rotatable to facilitate feeding of ink from the Int. 15/16 .346/l40; 401/258, 259, 260,

reservoir to the writing point of the pen. The pen is [58] Field of Search especially useful for automatic drawing machines l wherein writing or tracing speed IS llmlted by the rate of available ink supply flow to the pen point.

7 Claims, 1 Drawing Figure u Du s 2 TUBE WRITING PEN, PARTICULARLY FOR AUTOMATIC DRAWING MACHINES BACKGROUND OF THE INVENTION In conventional stylographic or tube writing pens comprising a cylindrical member which at one end forms a writing tube mount and which contains an internal bore for the reception of an axially movable dropweight carrying a clearing wire, the internal bore containing the dropweight communicates with the ink reservoir, permitting the ink from the reservoir to reach the writing tube through the internal bore and to flow out of the writing tube or pen point for forming a trace.

The rate of flow of ink from the writing tube is limited substantially by a capillary annular chamber between the inner wall of the writing tube and the clearing wire. Consequently the tracing speed of conventional tube writing pens is subject to a maximum speed above which the supply of ink is insufficient to provide a continuous trace of a desired width. This is particularly a drawback in automatic drawing equipment which, as such, admits of high drawing speeds but which cannot work at full capacity because of the limitation imposed on the rate ofink supply.

BRIEF DESCRIPTION OF THE INVENTION According to the present invention there is provided a stylographic or tube writing pen, wherein the pen comprises a cylindrical member which, at one end, forms a writing tube mount, and which is formed with an internal bore for the reception of an axially movable dropweight carrying a clearing wire, and wherein the surface of the dropweight is formed with a helical recess or groove, the dropweight being rotatable about its longitudinal axis.

Rotation of the dropweight causes the helical groove to convey ink to the writing tube and to generate in the front end part of the internal bore containing the dropweight a surplus of ink or a gauge pressure, so that the rate of discharge of the ink from the writing tube is increased.

Moreover, rotation of the helical groove applies forces to the ink which improve its viscosity, this likewise contributing towards permitting a higher drawing speed.

Preferably the helical groove extends axially along the entire length of the dropweight.

Rotation about its longitudinal axis can be imparted to the dropweight in various ways. As an example, the end of the dropweight remote from the clearing wire may be provided with an extension for coupling the same to a drive means. A flexible shaft may be attached to this extension and driven by a motor at a controllable speed.

Additional objectsand advantages of the invention will be more readily apparent from the following detailed description of an embodiment thereof when taken together with the accompanying drawing, in which:

The FIGURE is an axial sectional view through a pen schematically showing the invention.

Referring now to the drawing, there is shown a pen generally designated including a body portion 12 in the nature of a shaft-like holder. A cylindrical member 14 is screwed into the holder or body portion 12 and has an internal bore 16 which communicates with an ink reservoir 18 with an ink supply therein generally indicated at 20. A writing tube or pen point 22 is inserted into the bottom end of the cylindrical member 14 in a usual manner. In the region of the screw threads on the cylindrical member 14 by which thelatter is screwed into the holder 12, the member 14 is formed with a helical equalization chamber 24 in a known manner.

A dropweight 26 is slidably mounted and contained within internal bore 16 and attached to the bottom end of the dropweight is a clearing wire 28 which in a usual manner is extendable into the bore in writing tube or point 22. In the illustrated position, with the dropweight in its lowermost position, the clearing wire 28 projects from the bottom end of the writing tube. When the pen writes, the clearing wire 28 is pushed back in a conventional manner into the writing tube or point 22 and thus lifts the dropweight 26. This motion of the wire or the motion produced by corresponding shaking movements enables the writing tube to be kept clean and the flow of ink to be started.

Dropweight 26 has a helical groove or the like 30 formed on its longitudinal external surface and which in the illustrated embodiment has the form of a screw thread extending axially up the entire length of the dropweight.

In the position shown in the drawing, ink 20 enters the chamber 32 above the writing tube after flowing from reservoir 18 and through internal bore 16 and thence through channels or the like 34 formed in the bearing shoulder 36 as indicated by arrows 38. When the writing pen is applied to a sheet of paper or the like, the clearing wire 28 is pushed upwards and lifts the dropweight, permitting ink to flow in and the entire end base of the writing tube or pen point 22 rests on the paper. Up to a given drawing speed, for example 8 cm./sec., the illustrated pen functions in a conventional manner. However, when drawing speed is higher, the

rate of discharge of ink from writing tube or point 22 is insufficient for drawing a continuous trace of desired width. The present invention incorporates mechanism to overcome this deficiency.

The rate of ink discharged from the writing tube or pen point is controllable. As shown, dropweight 26 is provided at its upper end with a stud 40 or the like adapted for attachment of the dropweight to drive means which are schematically shown. The drive means can, for example, include an extension 42 of any desired construction such as a flexible cable, shaft, etc. attached to stud 40 for coupling the same to a drive means including a speed reducer 44 and a controllable speed drive motor 46 operatively driving stud 40 through the speed reducer and connecting means. As shown in the drawing, when viewed from stud 40, rotation of the stud and threaded dropweight 26 will be clockwise. In operation the helical groove 30 will convey ink from the ink reservoir 18 downward to the writing tube or pen point 22 and generate a gauge pressure below the bottom end of the dropweight. The rate of ink discharged from the writing tube is thus increased permitting a correspondingly higher drawing speed.

The speed of rotation of the dropweight can be adjusted according to the desired drawing speed in such a manner that the ink will be forcedoutofthe end of the writing tube at the exact rate needed .to meet the demands of drawing the desired width of trace at the desired speed.

The controllable drive rotating the dropweight, as schematically shown, can be varied or incorporate specifically different drive means.

Manifestly, minor changes in details of construction can be effected in the shown and described embodiment of the invention without departing from the spirit and scope thereof as defined in and limited solely by the appended claims.

We claim:

1. A stylographic pen comprising:

A. a body having:

i. a cylindrical member mounted therein formed with an internal bore in communication with a supply of ink;

B. an axially movable dropweight slidably mounted in said bore and mounting thereon a clearing wire;

C. a writing tube mounted at the end of said cylindrical member and operatively engageable by said clearing wire;

I D. the external surface of said dropweight having a helical recess formed thereon; and

E. said dropweight being rotatable about its longitudinal axis and adapted upon rotation to force the ink through said writing tube.

2. A stylographic pen as claimed in claim 1 and including means for rotating said dropweight at controlled speeds of rotation.

3. A stylographic pen as claimed in claim 2 wherein the helical recess extends over the entire axial length of said dropweight, said ink supply comprising an ink reservoir and at least a portion of the threaded dropweight operatively extending into said reservoir.

4. A stylographic pen as claimed in claim 3 including an extension on the end of said dropweight remote from said clearing wire adapted for coupling engagement with drive means for rotating said dropweight.

5. A stylographic pen as claimed in claim 4 wherein the drive means for rotating said dropweight includes a controllable speed drive motor and a speed reduction mechanism operatively connected to said drive motor.

6. A stylographic pen as claimed in claim 1 in combination with an automatic drawing machine wherein means are provided for rotatably driving said dropweight at a speed correlated with speed of operation of said drawing machine.

7. A stylographic pen as claimed in claim 5 in an automatic drawing machine wherein said drive means for rotating said dropweight is correlated with speed of operation of said automatic drawing machine to insure supply of a sufficient amount of ink to provide a continuous trace of a desired width at given speeds of operation of said automatic drawing machine.

UNITED STATES PATENT QFFECE QERTWECAE @F ETWN Patent N0- 3.711.861 Dated Ianuary 16, 1973 lnvent fl Ewald Lorenz and Holger Sorirg It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Change the issuance date from January 16, 1972,10 Ianuary 16,

(SEAL) Attest:

EDWARD M.FLETCHER-,JR.

Rene Tegtmeyer Attesting Officer Acting Commissioner of Patents F ORM PO-1050-(10-69) USCOMM-DC 60376-P69 -i use o-Jss-ru fr H 5. GOVERNMENT PRW-TINC nrnr UNI D STATES PATENT @FFIQE QERTWECATE F QQRREQ'HN Patent 3,711,861 January 16, 1973 Inv n fl Ewald Lorenz and Holqer Soring It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Change the issuance date from January 16 1972, te January 16 Signed and sealed this 10th da of Jul 1975;

(SEAL) Attest:

EDWARD M.FLETCHER-,JR. Rene Tegtmeyer Attesting Officer Acting Commissioner of Patents FORM PO-1050(10-69) 

1. A stylographic pen comprising: A. a body having: i. a cylindrical member mounted tHerein formed with an internal bore in communication with a supply of ink; B. an axially movable dropweight slidably mounted in said bore and mounting thereon a clearing wire; C. a writing tube mounted at the end of said cylindrical member and operatively engageable by said clearing wire; D. the external surface of said dropweight having a helical recess formed thereon; and E. said dropweight being rotatable about its longitudinal axis and adapted upon rotation to force the ink through said writing tube.
 2. A stylographic pen as claimed in claim 1 and including means for rotating said dropweight at controlled speeds of rotation.
 3. A stylographic pen as claimed in claim 2 wherein the helical recess extends over the entire axial length of said dropweight, said ink supply comprising an ink reservoir and at least a portion of the threaded dropweight operatively extending into said reservoir.
 4. A stylographic pen as claimed in claim 3 including an extension on the end of said dropweight remote from said clearing wire adapted for coupling engagement with drive means for rotating said dropweight.
 5. A stylographic pen as claimed in claim 4 wherein the drive means for rotating said dropweight includes a controllable speed drive motor and a speed reduction mechanism operatively connected to said drive motor.
 6. A stylographic pen as claimed in claim 1 in combination with an automatic drawing machine wherein means are provided for rotatably driving said dropweight at a speed correlated with speed of operation of said drawing machine.
 7. A stylographic pen as claimed in claim 5 in an automatic drawing machine wherein said drive means for rotating said dropweight is correlated with speed of operation of said automatic drawing machine to insure supply of a sufficient amount of ink to provide a continuous trace of a desired width at given speeds of operation of said automatic drawing machine. 